My 6YO DD and 7YO DS love their Draw Write Now books, and I do too.
We also have a subscription to Mark Kistler’s on-line drawing videos. They are more abstract, but he really teaches some drawing techniques that I see them using more and more in their free drawing.
I would too love art instruction with more mediums though. Around here, we have access to some great homeschool classes, but it just isn’t in the budget at the moment.